Most of the commercial wind turbines on the market today utilize a braking mechanism to help protect them from over-revving in high wind situations. This mechanism has drawbacks when the wind is greater than the braking mechanism can handle. In these cases, the braking mechanism can heat up to the point where it catches the lubricants in the generator housing on fire and complete failure of the wind turbine quickly follows. There are also drawbacks even when the braking mechanism is operating properly. In a situation where there are high winds and the brake is operating properly, the brake prevents the wind turbine from spinning and producing electricity during the very times when the wind is the strongest. If a solution were devised that could allow a wind turbine to safely continue operation in wind conditions greater than previously possible, the wind industry could both reduce losses due to braking mechanism failures as well as increase their energy production by producing electricity when other turbines have to remain offline.
When a permanent magnet comes into close proximity of a solid core winding such as the ones found in motors and generators there is a strong attraction created between the two which can cause a lockup or cogging effect at low or startup RPM ranges. This is a difficult problem to overcome in wind turbines due to the fact that there are many permanent magnets and solid core windings in close proximity to one another so that the turbine can produce sufficient energy output. A general practice in residential size wind turbine design is to utilize open core or air coil windings which are coils of copper wrapped around nothing but a hollow tube or wrapped around a form that is removed after the coil is wrapped. This absence of solid iron cores in the windings eliminates the lockup or cogging effect at low RPM ranges, but produces very little energy output as compared to solid core coils. In effect the main purpose of the wind turbine, namely to produce large amounts of clean energy, is negated by this fix to the cogging or lockup problem. Hence most residential size wind turbines are producing only a fraction of the energy that they could be producing if they were designed differently. In larger more expensive turbines there are a number of expensive and costly systems used to help reduce the cogging or lockup effects. They often handle these issues within an expensive gearbox. Currently there are a large number of challenges faced by the wind industry with regard to gearbox reliability. Gearbox failure accounts for most of the downtime per failure in wind turbines and significantly increases operation and maintenance costs. If a solution could be devised to eliminate the lockup or cogging effect at low RPM or startup speeds; while at the same time utilizing solid core generator coils to maximize energy production, the wind industry could enjoy a number of beneficial effects such as reduced size to power ratios, greater generation capacity and increased usage in urban areas due to smaller more energy dense designs.
Most conventional Horizontal Axis Wind Turbine designs are designed around an expensive unit often mounted hundreds of feet off the ground to accommodate all of the mechanisms necessary for directly facing into the wind, power generation as well as braking and gearbox mechanisms. This results in a large amount of expensive equipment being very high up in the air where maintenance workers receive hazard pay just to go up and perform routine maintenance on the turbines. It further complicates the problem when something is going wrong with the turbine because now someone has to risk their life to enter a potentially dangerous environment hundreds of feet off the ground. If a solution could be devised to keep the expensive and heavy parts on the ground it would eliminate a multitude of problems faced by the wind industry today.
Through applied effort, ingenuity, and innovation, Applicant has identified a number of deficiencies and problems with wind turbine cost, construction, and performance. Applicant has developed a solution that is embodied by the present invention, which is described in detail below.